Settings For Honeywell CM67 and Old Boiler

[michaeld121]

I've just bought a new Honeywell CM67 Room Thermostat to connect up to my ancient (20+ years old?) Potterton Kingfisher CF55 (open flued, gas fired).

I'm planning to replace the boiler in about a year, but before I install & configure the new thermostat, I want to check that I'm not doing anything that might upset the boiler. I'm particularly thinking of parameters like 'Minimum On Time', 'Cycle Rate' and 'Proportional Band Width'

Any advice on changing those settings for an antique boiler would be much appreciated.

Michael

[Set Square]

I don't think it's an issue. If you're replacing an old manual room stat, that won't have had any of these niceties! The boiler should be able to cope with anything you throw at it.

If you've got a gravity HW and pumped CH system - as seems possible - the CM67 won't control the boiler directly anyway - it will control the pump, and the boiler will cycle on its own stat.

[Dave Liquorice]

The only warning I've seen is in relation to the propotional control. It's not recomended to use that if the system uses motorised valves. Each cycle of the proportional control also cycles the valve. Normally

6 times per hour, rather more than the conventional system of open when cold close when hot...

Hopefully with some form of control to stop it firing just to keep the gravity loop warm.